<!DOCTYPE html>
<html lang="en">

<head>
  <meta charset="UTF-8">
  <meta http-equiv="X-UA-Compatible" content="IE=edge">
  <meta name="viewport" content="width=device-width, initial-scale=1.0">
  <title>Document</title>

</head>

<body style="height: 5000px;">
  <div style="position: fixed;bottom: 50px;cursor: pointer;">顶部</div>
  <script>
    let div = document.querySelector('div')
    div.addEventListener('click', () => {
      console.log(55);
      setInterval(() => {
        window.scroll(0, );
      }, 15);
    })
  </script>
</body>

</html>